Data recording method, data erasure method, data display method, storage device, storage medium, and program

ABSTRACT

The objective of the present invention is to manage reference movies using an index file, without causing the user to be perplexed. The reference movies are generated because of, for instance, the upper limit of the file size. The index file manages sets of information regarding the files being managed. Examples of these sets of information are information for determining whether or not a file is presented to the user, information for determining whether or not a file is original, and information indicating whether or not nondestructive editing has been done. Based on such information, the erasure, displaying a list, and so on are carried out. Thus, it is possible to manage the reference movies using the index file, without causing the user to be perplexed.

TECHNICAL FIELD

The present invention relates to a data recording method, data erasuremethod, data display method, storage device, storage medium, andprogram, concerning recording/erasing video or audio data to/from arandom-access storage medium such as a hard disk and an optical disk.

BACKGROUND ART

Digital video recording/reproducing devices (hereinafter, video diskrecorder) adopting disks as media have become popular. A recordingformat for such devices is often the Quicktime® file format or the AVI(Audio Video Interleave) file format, in consideration of compatibilitywith PCs (personal computers).

Japanese Laid-Open Patent Application No. 2001-84705 (Tokukai2001-84705; published on Mar. 30, 2001) discloses a method for managingcontents in a disk when the above-mentioned file format for PCs isadopted. Referring to FIG. 33, an outline of this method is given. Files2101 through 2103 of a disk 2105 correspond to respective scenes orshots being recorded, and each of these files is one Quicktime file(hereinafter, Quicktime movie file).

An index file 2100 stores a table of data in the disk 2105. There areentries corresponding to the respective Quicktime movie files. Eachentry stores sets of reduced (thumbnail) image data 2111 through 2113representing respective scenes, and the names of files including thesescenes.

To display an index to the user, miniature images 2121 through 2123produced by decoding the sets of miniature image data 2111 through 2113in the entry are caused to appear on a contents selection display 2107.The user then selects a file that he/she wants to reproduce or edit,from these miniature images on the contents selection display 2107.When, for instance, the user selects the miniature image 2123 andinstructs the reproduction of the same, a file 2103 including thecontents corresponding to the miniature image 2123 is acquired and thereproduction of the contents in the file 2103 starts.

The index file 2100 includes (i) pointers to respective files storingthe contents of the disk 2105 and (ii) sets of miniature image data.Thus, the contents selection display 2107 can be shown only be readingout the index file 2100 from the disk 2105, so that the time requiredfor causing the index display (contents selection display) to appear onthe screen is short. As the contents selection display 2107 isfrequently called, this reduction of the time greatly lighten thefrustration of the user.

It should be noted that, however, the above-mentioned conventional artcould make the user feel puzzled about the management of a referencemovie.

The adoption of a file formant for PCs makes it difficult to deal withlarge-volume video data. Since the Quicktime file format and the AVIfile format manage addresses with 32-bit information, the maximum filesize is 2³², i.e. about 4 GB (gigabyte). The maximum recording time forrecording video data with a bit rate of 10 Mbps is less than 60 minutes,thereby not to be sufficient for recording TV programs and the like.

To solve this problem, a method termed “reference movie” shown in FIG.34 is adopted. The following will discuss this reference movie. First, areference movie is produced by the following steps (1) through (4): (1)From the start of the recording, data is recorded to the file 2201; (2)when an amount of data in the file 2201 approaches to the maximum filesize thereof, the recording to the file 2201 is stopped and subsequentdata is recorded to the next file 2202; (3) when an amount of data inthe file 2202 approaches to the maximum file size thereof, subsequentdata is recorded to the next file 2203 in the same manner as above; (4)when the recording completes, management information is generated andstored in the file 2204.

To reproduce the recorded contents, the file 2204 is designated, and inaccordance with the management information stored therein, the contentsin the files 2201 through 2203 are reproduced in sequence. To allow thecontents be reproduced even if the file 2204 is deleted, the files 2201through 2203 also include the management information. In the presentcase, the files 2201 through 2203 are termed automatically-divided moviefiles, and the file 2204 is termed a control movie file.

Managing such a reference movie (automatically-divided movie and controlmovie) by the above-mentioned method using the index file causes aproblem which will be discussed below with reference to FIG. 35.Assuming that the files 2201 through 2204 are registered to the indexfile 2100 with the sets of miniature image data representing therespective files, the representative images 2221 through 2224corresponding to the files 2201 through 2204 appear on the contentsselection display 2107. This makes the user feel puzzled, because fourrepresentative images appear even if the user recorded only one scene.

Also on the occasion of erasing the reference movie, four representativeimages appears with respect to one scene, causing the erasing process tobe ambiguous.

The present invention was done to solve this problem, and thus aims forproviding a data recording method, data erasure method, data displaymethod, storage device, storage medium, and program, which allow theuser to manage a reference movie by an index file, with no perplexity.

DISCLOSURE OF INVENTION

To achieve the above-identified objective, a data erasure method of thepresent invention, for erasing a set of data corresponding to an entryin a table from a storage medium, the table being stored in the storagemedium and centrally managing sets of data at least including sets ofdivided data and control data referring to said sets of divided data,comprises the step of: (i) when said set of data is erased, identifyingwhether or not said set of data corresponding to said registered entryis initially-recorded data.

To achieve the above-identified objective, the data erasure method ofthe present invention is arranged in such a manner that, the step (i) iscarried out based on (I) information regarding whether or not said datamanaged by said registered entry has been divisional-recorded, (II)information regarding a relationship with data managed by another entry,and (III) a creation time of said set of data.

To achieve the above-identified objective, a data recording method ofthe present invention, which centrally manages sets of data asrespective entries, to a storage medium, is characterized in that, toeach of said entries, information regarding whether or not a set of datamanaged by the entry is initially-recorded data is recorded.

To achieve the above-identified objective, a data recording method ofthe present invention, which centrally manages sets of data asrespective entries, to a storage medium, is characterized in that, toeach of said entries, information regarding whether or not presence ofdata managed by the entry is presented to a user is recorded.

To achieve the above-identified objective, the data recording method ofthe present invention is arranged in such a manner that, said sets ofdata include at least sets of divided data and control data referring tosaid sets of divided data.

To achieve the above-identified objective, the data recording method ofthe present invention is arranged in such a manner that, to each of theentries, information regarding a relationship with data managed byanother entry is recorded.

To achieve the above-identified objective, the data recording method ofthe present invention is arranged in such a manner that the table isstored in a file.

To achieve the above-identified objective, a data erasure method of thepresent invention erases a set of data corresponding to an entry in atable from a storage medium, the table being stored in the storagemedium and centrally managing, as respective entries, sets of data atleast including sets of divided data and control data referring to saidsets of divided data, the data erasure method being characterized inthat, in the storage medium, information for identifyinginitially-recorded data is recorded to said entry corresponding to saidset of data to be erased, and the data erasure method beingcharacterized by comprising the step of: when erasing said set of data,determining whether or not said set of data is erasable, based oninformation regarding whether or not said set of data to be erased isthe initially-recorded data and information regarding a relationshipwith data managed by another entry.

To achieve the above-identified objective, a data erasure method of thepresent invention erases a set of data corresponding to an entry in atable from a storage medium, the table being stored in the storagemedium and centrally managing sets of data as respective entries, thedata erasure method being characterized in that, in the storage medium,(a) information regarding whether or not presence of said set of data ispresented to a user and (b) information regarding a relationship withdata managed by another entry are recorded to said entry correspondingto said set of data to be erased, and the data erasure method beingcharacterized by comprising the step of: when erasing said set of data,altering the information (a) in accordance with the information (b).

To achieve the above-identified objective, a data display method of thepresent invention, for reading out a table from a storage medium anddisplaying the table, the table being stored in the storage medium andcentrally managing sets of data as respective entries, is characterizedin that, in the storage medium, (A) information regarding whether or notpresence of said set of data is presented to a user is recorded to saidentry corresponding to said set of data, and in what way the table isdisplayed is determined in accordance with the information (A).

To achieve the above-identified objective, a storage device of thepresent invention, for recording, to a storage medium, a table whichcentrally manages sets of data as respective entries, is characterizedby comprising: means for recording, to each of said entries, informationregarding whether or not data managed by the entry is initially-recordeddata.

To achieve the above-identified objective, a storage device of thepresent invention, for recording, to a storage medium, a table whichcentrally manages sets of data as respective entries, is characterizedby comprising: means for recording, to each of said entries, informationregarding whether or not presence of data managed by the entry ispresented to a user.

To achieve the above-identified objective, a storage medium of thepresent invention, to which a table for centrally managing sets of dataas respective entries is recorded, is characterized in that, in each ofsaid entries, information regarding whether of not data managed by theentry is initially-recorded data is recorded.

To achieve the above-identified objective, a storage medium of thepresent invention, to which a table for centrally managing sets of dataas respective entries is recorded, is characterized in that, in each ofsaid entries, information regarding whether or not presence of datamanaged by the entry is presented to a user is recorded.

To achieve the above-identified objective, a program of the presentinvention causes a computer to implement any one of the above-describeddata erasure methods or any one of the above-described data recordingmethods.

A storage medium of the present invention is a computer-readable storagemedium recording the foregoing program.

According to the present invention, information for determining whetheror not a file recorded to the disk is an automatically-divided moviefile and information regarding for determining whether or not a file isoriginal are used as bases for making decision. Thus, even if anautomatically-divided movie file exists, erasure is carried out withoutcausing the user to feel perplexed.

Furthermore, according to the present invention, information fordetermining whether or not a file is original is recorded to a disk.Thus, even if an automatically-divided movie file exists, erasure iscarried out without causing the user to feel perplexed.

Furthermore, according to the present invention, information fordetermining whether or not an AV file corresponding to an entry ispresented to the user is recorded to a disk. Thus, the user canapparently erase arbitrary contents even if the file reference has beenmade.

For a fuller understanding of the nature and advantages of theinvention, reference should be made to the ensuing detailed descriptiontaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing an outline of a digitalrecording/reproducing device of an embodiment of the present invention.

FIG. 2( a) illustrates an example of the relationship between managementinformation and an AV stream in the Quicktime file format, FIG. 2( b)shows another example of the relationship between management informationand an AV stream in the Quicktime file format, and FIG. 2( c) shows afurther example of the relationship between management information andan AV stream in the Quicktime file format.

FIG. 3 illustrates an outline of a Movie atom in the Quicktime fileformat.

FIG. 4 illustrates an outline of a Track atom in the Quicktime fileformat.

FIG. 5 illustrates a structure of a Track header atom in the Quicktimefile format.

FIG. 6 illustrates a structure of a Media atom in the Quicktime fileformat.

FIG. 7 illustrates a structure of a Media information atom in theQuicktime file format.

FIG. 8 illustrates a structure of a Sample table atom in the Quicktimefile format.

FIG. 9 shows an example of data management using the Sample table atom.

FIG. 10 illustrates a structure of an Edit atom in the Quicktime fileformat.

FIG. 11( a) shows the content of an Edit list atom, FIG. 11( b) shows anexample of a sample, and FIG. 11( c) shows the order of reproducing thesample.

FIG. 12 illustrates a structure of a User data atom in the Quicktimefile format.

FIG. 13 illustrates a structure of an AV stream.

FIG. 14 illustrates a structure of a Video Unit (VU).

FIG. 15 illustrates how the AV stream is managed in the Quicktime.

FIG. 16 illustrates a reference device model.

FIG. 17 illustrates a structure of an AV Index file.

FIG. 18 shows a structure of attribute information.

FIG. 19 shows pe-flags in First Embodiment of the present invention.

FIG. 20 is a flowchart of a recording operation.

FIG. 21 illustrates the attribute information after the recording inFirst Embodiment of the present invention.

FIG. 22 illustrates the attribute information after nondestructiveediting in First Embodiment of the present invention.

FIG. 23 is a flowchart of an operation to determine whether or not afile is erasable in First Embodiment of the present invention.

FIG. 24 is a flowchart of an operation to tell whether a file is anoriginal file or a nondestructive-edited file in First Embodiment of thepresent invention.

FIG. 25 illustrates pe-flags of Second Embodiment of the presentinvention.

FIG. 26 illustrates attribute information after recording in SecondEmbodiment of the present invention.

FIG. 27 illustrates the attribute information after nondestructiveediting in Second Embodiment of the present invention.

FIG. 28 illustrates pe-flags of Third Embodiment of the presentinvention.

FIG. 29 illustrates attribute information after recording in ThirdEmbodiment of the present invention.

FIG. 30 illustrates the attribute information after nondestructiveediting in Third Embodiment of the present invention.

FIG. 31 illustrates attribute information after after-recording in ThirdEmbodiment of the present invention.

FIG. 32 is a flowchart of an erasing operation in Third Embodiment ofthe present invention.

FIG. 33 illustrates an index file of a conventional art.

FIG. 34 explains a concept of a reference movie in the conventional art.

FIG. 35 illustrates an index file for managing the reference movie inthe conventional art.

FIG. 36 illustrates an example of an improved index file for managingthe reference movie in the conventional art.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below withreference to the attached figures. Arrangements shared by allembodiments will be discussed first, and then descriptions specific torespective embodiments will be given.

<System Configuration>

FIG. 1 shows a structure of a digital video recording/reproducing device(video disk recorder) adopting disks as media. As shown in FIG. 1, thisdevice, which is shared by all embodiments of the present invention,includes a bus 100, host CPU 101, RAM 102, ROM 103, user interface 104,system clock 105, optical disk 106, pickup 107, ECC (Error CorrectingCoding) decoder 108, ECC encoder 109, reproducing buffer 110,recording/after-recording buffer 111, demultiplexer 112, multiplexer113, multiplexing buffer 114, audio decoder 115, video decoder 116,audio encoder 117, video encoder 118, and other members which are notillustrated in the figure, such as a camera, microphone, speaker, anddisplay. Note that, the after-recording is an operation to add audiodata to video data which is initially recorded.

The host CPU 101 controls, through the bus 100, the demultiplexer 112,multiplexer 113, pickup 107, audio decoder 115, video decoder 116, audioencoder 117, and video encoder 118 (despite the members 115 through 118are not connected to the bus 100 in the figure).

On the occasion of reproduction, data being read out from the opticaldisk 106 by the pickup 107 is subjected to error-correction in the ECCdecoder 108, and temporarily held in the reproducing buffer 110. Inresponse to a data transmission request from the audio decoder 115 andvideo decoder 116, the host CPU 101 instructs the demultiplexer 112 todistribute sets of data in the reproducing buffer 110 to decodersappropriate to the respective types of data, with reference tomanagement information regarding the data being reproduced.

In the meantime, on the occasion of recording, data having beencompressed and coded by the audio encoder 117 and video encoder 118 issupplied to the multiplexing buffer 114, AV-multiplexed by themultiplexer 113, and then supplied to the recording/after-recordingbuffer 111. The ECC encoder 109 adds an error-correction code to thedata held in the recording/after-recording buffer 111, and then the datais recorded to the optical disk 106 by the pickup 107.

In the present case, audio data is coded with the MPEG-1 Layer-II, whilevideo data is coded with the MPEG-2.

The optical disk 106 is a removable optical disk in which data is readout or recorded from the periphery to the center in a spiral manner. Onesector is made up of 2048 bytes, and an ECC block is made up of 16sectors for the sake of error-correction. To rewrite data in the ECCblock, it is necessary to carry out the following steps: the whole ECCblock including that data is read out, error-correction is carried outso that the data is rewritten, the error-correction code is added again,an ECC block is constructed and then recorded in a storage medium. Theoptical disk 106 adopts the ZCAV (Zone Constant Angular Velocity) inorder to improve the efficiency of the recording, so that a recordingarea is made up of a plurality of zones having different rotationspeeds.

<File System>

A file system is used for managing various types of information recordedin the optical disk 106. As such file system, the UDF (Universal DiskFormat) is adopted in consideration of the compatibility with PCs(personal computers). In this file system, all sorts of managementinformation and AV streams are dealt with as files.

In the above-described video disk recorder, the host CPU 101 carries outthe recording of data to the optical disk 106 and the reproduction ofdata from the optical disk 106, using the file system. That is to say,the host CPU 101 functions as a file management section which records,reproduces, and erases data using file management information of thefile system. Information regarding files, e.g. attribute information ofa file, is also recorded to the optical disk 106 and read out from theoptical disk 106 under the control of the host CPU 101.

A user area is managed with a 2048-byte logical block (one-to-onecorresponding to the sector). Each file is made up of an integral numberof extents (consecutive logical blocks). A file may be recorded in sucha manner that its extents are recorded in different locations. A freearea is managed in logical blocks by Space Bitmap.

<File Format>

A Quicktime file format is adopted as a format for AV stream management.This Quicktime format which was created by Apple Computer, Inc. is apopular format for multimedia data management in the realm of PCs.

The Quicktime format is made up of data such as video data and audiodata (collectively termed media data or AV stream) and managementinformation. In the present case, the data and management informationare paired up and termed a Quicktime movie (“movie” for short). The dataand management information being paired up may be stored in one file orin different files.

When being stored in one file, the data and management information arearranged as shown in FIG. 2( a). Different types of information arestored in respective “atoms” which are based on a common structure. Themanagement information is stored in “Movie atom”, while the media datais stored in “Movie data atom”. Note that, the management information inthe Movie atom includes: a table for identifying a relative location ofthe media data in the file at a certain time; attribute information ofthe media data; below-mentioned external reference information; and soon. In other words, the management information in the Movie atomincludes a table for, for instance, centrally managing sets of data asentries.

When being stored in different files, the management information andmedia data are arranged as shown in FIG. 2( b). In this case, while themanagement information is stored in the Movie atom, the media data isnot necessarily stored in an atom. This condition is described as theMovie atom “externally refers to” the file storing the media data.

As illustrated in FIG. 2( c), it is possible to externally refer to aplurality of AV stream files. This makes it possible to realize“nonlinear editing”, i.e. “nondestructive editing” which enables theuser to apparently carry out editing without changing the locations ofAV streams.

Now, a format of management information in Quicktime will be discussedwith reference to FIGS. 3 through 12. First, “atom”, which is a commoninformation storing format, is described. At the head of an atom, “Atomsize” indicating the size of the atom and “Type” indicating the type ofthe atom always exist. Four characters are given to each Type, e.g.‘moov’ for the Movie atom and ‘mdat’ for the Movie data atom.

Each atom can include another atom, i.e. atoms are arranged in ahierarchy. FIG. 3 shows how the Movie atom is structured. “Movie headeratom” manages overall attribute of the movie managed by the Movie atom.“Track atom” stores information concerning tracks such as a video trackand an audio track in the movie. “User data atom” is a user-definedatom.

FIG. 4 shows how the Track atom is structured. “Track header atom”manages overall attribute of the track. “Edit atom” determines whichpart of the media data is reproduced at which timing of the movie.“Track reference atom” manages the relationship between the own trackand another track. “Media atom” manages data such as video data andaudio data.

FIG. 5 shows how the Track header atom is structured. Note that,descriptions are given only to those required for the discussion below.“Flags” is a collection of flags indicating attributes. A major exampleof such flag is “Track enabled flag”. When this flag is 1, the trackhaving the flag is reproduced. On the other hand, when the flag is 0,the track is not reproduced. “Layer” indicates a spatial priority of thetrack having the Layer. When there are a plurality of tracks fordisplaying an image, a track having a Layer with smaller value comes infront. “Edit atom” will be described later.

FIG. 6 shows how the Media atom is structured. “Media header atom”manages overall attribute and the like concerning media data managed bythe Media atom. “Handler reference atom” stores information indicatingwhich decoder decodes the media data. “Media information atom” managesattribute information peculiar to each video/audio media data.

FIG. 7 shows how the Media information data is structured. “Mediainformation header atom” manages attribute information peculiar to eachvideo/audio media data. “Handler reference atom” has already beendescribed in association with the Media atom. “Data information atom”includes “Data reference atom” which manages the name of a fileincluding media data to which the Quicktime movie refers. “Sample tableatom” manages the size of data, reproduction time, and the like.

Next, how the Sample table atom is structured will be discussed withreference to FIG. 8. First, a method of managing data in Quicktime isdescribed with reference to FIG. 9. In Quicktime, a minimum unit of data(e.g. video frame) is termed “sample”. For each track, samples havenumbers (sample numbers) starting from 1, which indicate the order ofreproduction.

Also, in the Quicktime format, the reproduction time and data size ofeach sample are in control. A field in a file, in which samplespertaining to one track are successively provided in the order ofreproduction, is termed “chunk”. Chunks also have numbers starting from1, which indicate the order of reproduction.

In the Quicktime format, moreover, the address of each chunk, theaddress being counted from the head of the file, and the number ofsamples in each chuck are in control in accordance with suchinformation, the location of a sample corresponding to a particular timeis figured out.

FIG. 8 shows how the Sample table atom is structured. A Sampledescription atom manages a Data format of each chunk, an Index of thechunk of the file in which the sample is stored, and the like. ATime-to-sample atom manages a reproduction time of each sample.

“Sync sample atom” manages samples that can be decoded. “Sample-to-chunkatom” manages the number of samples in each chunk. “Sample size atom”manages the size of each sample. “Chunk offset atom” manages the addressof each chunk, the address being counted from the head of the file.

Now, a briefing on “Edit atom” is given. As shown in FIG. 10, the Editatom includes one “Edit list atom”. This Edit list atom has entries ineach of which values of “Track duration”, “Media time”, and “Media rate”are provided. The number of the entries is designated by “Number ofentries”. The entries correspond to fields which are successivelyreproduced on the track, and the order of the entries correspond to theorder of reproduction of the fields.

The Track duration indicates the reproduction time of a field on thetrack, the field being managed by the entry. The Media time indicatesthe location of the head of the field on the media data. The Media rateindicates the speed of reproducing the field. Note that, when the Mediatime is −1, the reproduction of samples on that track is paused for theTrack duration of the entry. This field is termed “empty edit”.

In this manner, in the Quicktime file format, the Edit atom, which isincluded in the Track atom in the Movie atom storing the managementinformation, includes the Edit list atom for centrally managing sets ofdata as entries.

FIG. 11 shows an example illustrating how the Edit list is used. FIGS.11( a), 11(b), and 11(c) illustrate an example of reproduction rangespecification by the Edit atom. In the present case, the contents of theEdit list atom are as shown in FIG. 11( a), and the structure of asample is as shown in FIG. 11( b). Also, it is assumed that the Trackduration of the i-th entry is D(i), the Media time of the i-th entry isT(i), and the Media rate of the i-th entry is R(i). The reproduction ofsamples is in reality carried out in the order shown in FIG. 11( c).These assumptions are now briefly described.

First, in the entry #1, the Track duration is 13000, the Media time is20000, and the Media rate is 1. Thus, in the field from the head of thetrack to 13000, the field from the time 20000 to the time 33000 in thesample is reproduced. Next, in the entry #2, the Track duration is 5000and the Media time is −1. Thus, in the field from the time 13000 to thetime 18000 in the track, no reproduction is carried out.

At the end, in the entry #3, the Track duration is 10000, the Media timeis 0, and the Media rate is 1. Thus, from the time 18000 to the time28000 of the track, the field form the time 0 to the time 10000 in thesample is reproduced.

FIG. 12 shows how the User data atom is constructed. This atom can storean arbitrary number of sets of original information which are notdefined by the Quicktime format. One set of original information ismanaged by one entry, and one entry is made up of “Size”, “Type”, and“User data”. The Size indicates the sizes of the entry, the Type is anidentifier for distinguishing between the sets of original information,and the User data indicates actual data.

<Structure of AV Stream>

The following will describe how the AV stream which is common to allembodiments of the present invention, with reference to FIGS. 13 and 14.One AV stream is made up of an integral number of Record Units (RUs). AnRU is a unit for sequential recording on the disk. The length of the RUis determined in such a manner as to assure seamless reproduction(images and sounds are reproduced without interruption) and real-timeafter-recording (sounds are recorded while the images to which thesounds are after-recorded are seamlessly reproduced) in whatever mannerthe RUs constituting the AV stream are provided on the disk. Thisdetermination of the length will be described later.

The stream is constructed in such a manner as to cause an RU border tocorrespond to an ECC block border. Since the RU has suchcharacteristics, it is possible to easily change the locations of theRUs on the disk while keeping the seamless reproduction, even afterrecording the AV stream on the disk.

One RU is made up of an integral number of Video Units (VUs). A VU is aminimum unit that can be reproduced by itself, thereby being able tofunction as an entry point of the reproduction.

FIG. 14 shows how the VU is structured. One VU is made up of: anintegral number GOPs (Group Of Pictures) each storing video data forabout one second; and an integral number AAUs (Audio Access Units) eachstoring main audio data reproduced concurrently with the correspondingvideo data.

Note that, the GOP is a unit of video compression under the MPEG-2 videostandard, and made up of a plurality of (typically about 15) videoframes. The AAU is a unit of audio compression under the MPEG-1 Layer IIstandard, and made up of 1152 audio wave sample points. When a samplingfrequency is 48 kHz, a reproduction time per AAU is 0.024 second. In theVU, the AAU and the GOP are provided in this order in order to reducethe delay required for carrying out audio/video synchronousreproduction.

To realize the reproduction of each VU by itself, “Sequence Header” (SH)is provided at the head of each set of video data in the VU. Thereproduction time of the VU is defined by the multiplication of thenumber of video frames in the VU by the cycle of the video frames. Toconstitute one RU by an integral number of VUs, the ends of therespective VUs are set at 0 in order to cause the head and terminal ofthe RU to correspond to the ECC block border.

<Method of Managing AV Stream>

A method of managing the AV stream is based on the above-mentionedQuicktime file format. FIG. 15 shows how the AV stream is managed. Videodata and audio data are managed by a video track and an audio track,respectively. In the video track, the management is carried out in sucha manner that one video frame is dealt with as one sample, and a seriesof GOPs in the VU is dealt with as one chunk. In the audio track,meanwhile, the management is carried out in such a manner that one AAUis dealt with as one sample and a series of AAUs in the VU is dealt withas one chunk.

<Method of Determining RU>

Next, how the RU is determined is discussed. According to this method,one device is assumed as a reference (i.e. a reference device model),and keeping this assumption in mind, a unit for sequential recording isdetermined in such a manner as not to interrupt the seamlessreproduction.

First, the reference device model is described with reference to FIG.16. The reference device model is made up of: one pickup; ECC encoderand decoder 501 connected to the pickup; a track buffer 502; ademultiplexer 503; an after-recording buffer 504; an audio encoder 509;a video buffer 505; an audio buffer 506; a video decoder 507; and anaudio decoder 508.

It is assumed here that the seamless reproduction in the present modelis assured on condition that, at the start of decoding the VU, at leastone VU exists on the track buffer 502. The speed of inputting audioframe data to the ECC encoder 501 and the speed of outputting the datafrom the ECC decoder 501 are both determined as Rs.

Moreover, the maximum period for pausing the reading and recordingcarried out by accessing is determined as Ta, and a period required fora short access (about 100 tracks) is determined as Tk. Note that, eachof these periods includes a period for seeking, a period for waiting forthe rotation, and a period from the access to the output of data whichis initially read out from the disk, the data being outputted from theECC. In the present embodiment, Rs=20 Mbps, Ta=1 second, and Tk=0.2second.

When the reproduction is carried out using the above-described referencedevice model, it is possible to assure that there is no underflow of thetrack buffer 502, if the following condition is met.

Before describing the condition, the definitions of symbols are given asfollows: The i-th successive field constituting the AV stream is C#i,and the reproduction time included in the C#i is Tc(i). Tc(i) is anaggregate of the reproduction times of the VUs whose heads are includedin the C#i. Also, a period of time for accessing from the C#i to theC#i+1 is Ta.

Furthermore, a period of time of reading out VUs corresponding to thereproduction time Tc(i) is Tr(i). With these symbols in mind, thecondition with which the underflow of the track buffer 502 does notoccur is represented by the following formula for an arbitrary C#i,provided that the maximum reading time including the jumping betweendiscrete sets of data is Tr(i).

Tc(i)≧Tr(i)+Ta  <Formula 1>

This is because, this formula is a sufficient condition to meet thefollowing sufficient condition for the seamless reproduction.

Σ_(i) Tc(i)≧Σ_(i)(Tr(i)+Ta)

Substituting Tr(i)=Tc(i)×(Rv+Ra)/Rs for Tr(i) in Formula 1 and solvingthe formula for Tc(i), the following condition of Tc(i), which canassure the seamless reproduction, is obtained.

Tc(i)≧(Ta×Rs)/(Rs−Rv−Ra)  <Formula 2>

In other words, the seamless reproduction is assured if the aggregate ofthe VUs whose headers are included in the respective successive fieldsmeets the formula above. On this occasion, it is possible to set alimitation in such a manner as to cause the respective successive fieldsinclude complete groups of VUs in which the total reproduction timesmeet the formula above.

In the automatically-divided movie file, it is also necessary to meetFormula 2. However, the first RU of the first automatically-dividedmovie and the last RU of the last automatically-divided movie do notnecessarily meet Formula 2, because of the following reasons: The firstRU can be compensated by causing the start of the reproduction to belater than the start of reading out data from the storage medium.Meanwhile, regarding the last RU, it is unnecessary to care about thesuccessive reproduction as no data follows this RU. Loosening theconditions with regard to the first and last RUs, it is possible toeffectively utilize free areas which are short.

<Index File>

To manage various types of files (hereinafter, Av files) in the opticaldisk 106, e.g. Quicktime movies and static image data, one specialQuicktime movie file termed an AV Index file is provided in the disk.FIG. 17 shows this AV index file. Being identical with a usual Quicktimemovie file, the AV index file is made up of a Movie atom 1791 which ismanagement information and a Movie data atom 1792 which is actual data.

The AV Index file manages a plurality of entries. Each AV file in thedisk is managed by a corresponding entry. Further, a folder in which theAV file is stored is also managed by a corresponding entry. In thepresent embodiment, files in the disk (optical disk 106) are managed bythe AV Index file using entries. A table for managing the entries isthus stored in the AV Index file.

The Movie atom 1791 is made up of the following four tracks: a Propertytrack 1793 for managing sets of attribute information of the respectiveentries; a Title track 1794 for managing sets of title character stringdata of the respective entries; a Thumbnail track 1795 for managing setsof representative image data of the respective entries; and an Intromusic track 1796 for managing sets of representative audio data of therespective entries.

The sets of attribute information, title character string data,representative image data, and representative audio data regarding therespective entries are managed as samples in the respective tracks 1793through 1795. Taking the AV file 1741 as an example, the attributeinformation is managed by the sample 1701 on the Property track 1793,the title character string data is managed by the sample 1711 on theTitle track 1794, the representative image data is managed by the sample1721 on the Thumbnail track 1795, and the representative audio data ismanaged by the sample 1731 on the Intro music track 1796. The samplesare coordinated with each other in accordance with the reproductionstart times of the respective samples. That is, it is determined thatsamples which are on different tracks but reproduced in an identicalperiod correspond to the same entry.

In this manner, the Movie atom 1791 stores the attribute information,title character string data, representative image data, andrepresentative audio data concerning each AV file. A set of theattribute information is structured as shown in FIG. 18. The fields arearranged as follows. “Version” indicates a version of the file format.“Pe-flags” is a collection of different types of flags, and will bedescribed later.

“Parent-entry-number” stores an entry-number of an entry correspondingto a folder including an entry corresponding to the attributeinformation. “Entry-number” stores an entry number of the entrycorresponding to the attribute information. These two sets ofinformation indicate the inclusive relation between files and folders.Descriptions regarding “set-dependent-flags” and “user-private-flags”are omitted.

“Creation-time” indicates when the entry corresponding to the attributeinformation is generated (i.e. indicates the creation time), while“modification-time” indicates when the entry corresponding to theattribute information is modified. “Duration” indicates a reproductiontime of the entry corresponding to the management information. When theentry corresponding to the attribute information corresponds to a file,the pathname of this file is encoded as “binary-file-identifier” in afixed length. A detailed description of this binary-file-identifier isomitted.

“Referred-counter” records how many times a file managed by the entrycorresponding to the attribute information is referred to by anotherfile. That is, the referred-counter is equivalent to the informationconcerning the relationship with a file managed by another entry.“Referring file list” stores a list of pathnames of files that areactually referred to. “URL file identifier” stores, when the managedfile cannot be encoded as the binary-file-identifier, the path of thefile in the URL (Unified Resource Locator) format.

Other types of data stored in the Movie atom 1791 are now discussed. Therepresentative image data is JPEG-reduced images each having the size of160×120 pixels, the title string data is text data, and therepresentative audio data is data compressed under MPEG-1 AudioLayer-II.

First Embodiment

The following will describe First Embodiment of the present inventionwith reference to FIGS. 19 through 24. In the present embodiment, theattribute information of the AV Index file is caused to include a flagfor identifying an automatically-divided movie file. Based on this,image reproductions and deletion of files are properly carried out,thereby preventing the user from being perplexed.

<Management Information Format>

The formats of the Quicktime movie file and the AV Index file have beendescribed above. The pe-flags field of the attribute information (FIG.18) of the AV Index file is defined as shown in FIG. 19. Respectivefields therein are discussed below. “Attribute of Entry” records thetype of a layer to which an entry corresponding to the Property entrybelongs. Regarding the layer, no further description is given here.

“Type of Entry” stores information for telling whether the correspondingentry is a file or a folder. No descriptions are given here to “Usage ofEntry” and “Status of Entry”. “Data reference of corresponding AV file”is a flag for, when the corresponding entry manages an AV file,identifying whether or not the entry refers to another AV file.

“Structural status of corresponding AV file” is a flag for identifyingwhether or not the corresponding entry is an automatically-divided moviefile, and is set to 1 when the entry is an automatically-divided moviefile. “Security status of corresponding AV file” is a flag for, when thecorresponding entry manages an AV file, identifying whether or not theentry is encrypted.

“Content type of corresponding AV file” is a field for storing, when thecorresponding entry manages an AV file, the type of contents included inthat file. In this manner, in the present embodiment, thereferred-counter in the attribute information of the Movie atom in theAV Index file counts how many times the file managed by thecorresponding entry is referred to by another file. Further, theStructural status flag of corresponding AV File of the pe-flags in theattribute information of the Movie atom in the AV Index file identifieswhether or not the corresponding entry is an automatically-divided moviefile. In the following, how the attribute information including thesefields is used is described.

<Steps for Recording>

Referring to FIG. 20, steps carried out when the user instructsrecording are discussed. The AV stream to be recorded has a video bitrate Rv of 5 Mbps, audio sampling frequency of 48 kHz, and the bit rateRa of 256 kbps. It is assumed that the management information of thefile system has been read by the RAM 102.

First, the structure of the stream and the structure of the successivefields are determined (Step S701). Provided that one VU is 1GOP=30frames, Rs=20 Mbps, Ta=1 second, and Ra=256 kbps are substituted intoFormula 2, and the range of the Tc(i) which is not less than 1.36seconds is acquired. Since the reproduction time of one VU is 0.5second, the reproduction time of the RUs is 2 seconds.

Next, the recording of the movie file is prepared (S702). Morespecifically, the file is opened and a free area which can successivelyrecord one RU is searched. If no such free area, the recording isinterrupted and the user is informed that the recording cannot becarried out.

Also, the audio encoder 117 and the video encoder 118 are activated(S703). Then whether or not the recording buffer 111 stores data for oneRU is checked (S704).

If the data is stored, the data for one RU in the recording buffer 111is successively recorded to the optical disk 106 (S705). Then the sizeof the file being currently recorded is checked (S706). If the file sizemay exceed 4 GB after the recording of the next RU, the managementinformation of the movie file that is currently recorded is recorded(S707), and the recording of a new movie file is prepared to allow thesubsequent data to be recorded to another movie file (S708). After S708,the process goes back to S703 in order to record the data for the nextone RU. even if the file size does not exceed 4 GB after the recordingof the next RU, the process goes back to S703.

If data for 1RU has not stored in S704, the presence of an instructionto terminate the recording is checked (S709). S704 is carried out if theinstruction has not been made, while the following recording terminationprocess is carried out if the instruction has been made. In the process,first, the remaining data is recorded to the movie file which iscurrently engaging in the recording (S710), and the managementinformation is recorded (S711).

Next, whether or not the automatic division has been carried out ischecked (S712). If the automatic division has been done, a control moviefile is generated (S713). Finally, the Quicktime movie file thusgenerated is registered to the AV Index file (S714). When the automaticdivision has been done, the automatically-divided movie file and acontrol file are registered. If the automatic division has not beendone, one Quicktime movie file is registered. The process also goes toS714 also when the automatic division has not been done in S712.

Referring to FIG. 21, the following will describe how the attributeinformation to be registered to the AV Index file 1800 is set. First, acase where the attribute information is automatically divided andrecorded as automatically-divided movie files 1801 and 1802 and acontrol movie file 1803 is discussed. Note that, theautomatically-divided movie files 1801 and 1802 correspond to divideddata and the control movie file 1803 corresponds to control datareferring to the divided data.

Since the automatically-divided movie files 1801 and 1802 haveautomatically been divided, the Structural status of corresponding AVFile of the pe-flags is set to 1 (auto-divided). Also, being referred toby the control movie file 1803, the referred-counter of the attributeinformation entry is set to 1. The referring-file-list is set to 3 whichis the entry-number of the control movie file 1803.

Meanwhile, as the control movie file 1803 is not referred to by anotherfile, the referred-counter is set to 0. Not being automatically divided,the Structural status of corresponding AV File of the pe-flags is set to0.

Next, a normally-recorded movie file 1804 which is recorded without theautomatic division is discussed. Since this normally-recorded movie file1804 is not referred to by another file, the referred-counter is set to0. Also, as the automatic division is not carried out, the Structuralstatus of corresponding AV File of the pe-flags is set to 0.

<Steps for Nondestructive Editing>

A method of managing the AV Index file when the nondestructive editingis carried out will be discussed with reference to FIG. 22. First, acase where a Quicktime movie not being automatic-divided is subjected tothe nondestructive editing is described. Assume the following: in the AVIndex file 1800, the normally-recorded movie file 1804 is registered,and a nondestructive-edited movie file 1805 is generated with partlyreference to the normally-recorded movie file 1804.

In this case, since a value included in the attribute information entryof the normal movie file 1804 registered in the AV Index file 1800 isreferred to by the nondestructive-edited movie file 1805, thereferred-counter is set to 0. To the referring-file-list, theentry-number of the nondestructive-edited movie file 1805, i.e. 5 isrecorded.

Not being automatically divided, the Structural status of correspondingAV File of the pe-flags is set to 0. Meanwhile, since a value in theattribute information entry of the nondestructive-edited movie file 1805is not referred to by another file, the referred-counter is set to 0.Furthermore, not being automatically divided, the Structural status ofcorresponding AV File of the pe-flags is set to 0.

Next, a case where a Quicktime movie having been automatically dividedis subjected to the nondestructive editing is discussed. Assume that anondestructive-edited movie file 1806 which refers to a part of aQuicktime movie which is recorded after being automatically divided intoautomatically-divided movie files 1801 and 1802 and a control movie file1803 is generated.

In this case, the values in the attribute information entries of therespective automatically-divided movie files 1801 and 1802 are referredto by the control movie file 1803 and the nondestructive-edited moviefile 1806. Thus, the referred-counter is set to 2. Thereferring-file-list records 3 and 6 which are the entry-numbers of thecontrol movie file 1803 and the nondestructive-edited movie file 1806,respectively.

Also, being automatically divided, the Structural status ofcorresponding AV File of the pe-flags is set to 1. Since the values inthe attribute information entries of the control movie file 1803 and thenondestructive-edited movie files 1805 and 1806 are not referred to byanother file, the referred-counter is set to 0. Furthermore, not beingautomatically divided, the Structural status of corresponding AV File ofthe pe-flags is set to 0.

<Steps for Showing Contents Selection Display>

To the user, thumbnail images corresponding to the attribute informationentries in which the Structural status of corresponding AV Files of thepe-flags are set to 0 are displayed. In a case shown in FIG. 22,thumbnail images corresponding to the entry-numbers 3, 4, 5, and 6 aredisplayed. In this manner, whether or not thumbnail images are shown onthe contents selection display may be determined in accordance with aflag (information regarding whether or not the divisional recording hasbeen done) which identifies whether or not, for instance, thecorresponding entry among the attribute information entries of the moviedata is an automatically-divided movie file. From the thumbnail imageson the contents selection display, the user can select a thumbnail imagecorresponding to a desired file, and reproduce or erase the file.

<Steps for Erasure>

Either one of the following two types of operation guidelines can beexercised when the user instructs the erasure through the contentsselection display.

(Operation Guideline 1) An AV file generated through the nondestructiveediting is determined as erasable, while an AV file generated throughother ways is determined as erasable, on condition that that AV file isnot referred to by a nondestructive editing movie. Note that, if theautomatically-divided movie file is referred to by a nondestructiveediting movie, the control movie file controlling thatautomatically-divided movie file is also treated as being referred to bythe same nondestructive editing movie file.

(Operation Guideline 2) An AV file not being referred to by another AVfile is determined as erasable.

The operation guideline 1 is based on such an idea that the original(initially recorded) data recorded by the user is differentiated fromthe results of editing which are derived from the original data, inorder to conserve the original data as much as possible. Meanwhile, theoperation guideline 2 is based on such an idea to prevent the erasure ofone AV file from influencing on other AV files.

The original data in this case indicates, for instance, a recordedimage/audio data which has not been edited. On the other hand,non-original data is an AV file after being subjected to the editing.Thus, for instance, a file being subjected to the nondestructive editingis non-original data.

When accessing data using the file system, for instance, a file oforiginal data is expressed as an original file, and an entry of theoriginal file is expressed as an original entry.

The following will describe the steps carried out for implementing theseoperation guidelines.

<Steps for Erasure (Based on Operation Guideline 1)>

In FIG. 22, the entries with the entry-numbers 5 and 6 correspond tomovies generated as a result of nondestructive editing, and the entrieswith the entry-numbers 3 and 4 are sets of original data to which therespective movies with the entry-numbers 5 and 6 refer. Thus, when theuser designates the entries with the entry-numbers 5 and 6 as thetargets of erasure, these entries are erased. In the meantime, when theuser designates the entries with the entry-numbers 3 and 4 as thetargets of erasure, the erasure is refused or a warning is given to theuser.

Referring to FIG. 23, a process of determining erasability is discussed.First, to check whether or not the AV file corresponding to thedesignated entry is referred to by another AV file, the referred-counterof the designated entry is examined. When the referred-counter is 1 ormore, it is determined that the AV file is referred to by another AVfile and thus cannot be erased (S801). In the example shown in FIG. 22,the referred-counter of the movie file 1804 is 1 and thus cannot beerased. When the referred-counter is 0, the process goes to S802.

Next, whether or not the AV file corresponding to the designated entryexternally refers to another AV file is checked. When no file isreferred, it is determined that the erasure can be carried out (S802).Whether or not the AV file externally refers to another AV file can bechecked by examining the Data reference of corresponding AV File.Alternatively, the external reference can be checked by examiningwhether or not the referring-file-list of another entry includes theentry-number of the designated entry.

Then whether or not the designated AV file is a movie generated as aresult of nondestructive editing is checked (S803). The steps forachieving this is discussed with reference to a flowchart in FIG. 24.First, all entries having the referring-file-lists including theentry-number of the designated entry are listed, and the values of theStructural status of corresponding AV File of the respective listedentries are examined (S901). In this manner, whether or not each ofthese entries is recorded in a divided manner (i.e. automaticallydivided) is checked.

If none of these values is 1 (automatically-divided), it is determinedthat the designated AV file is a movie generated as a result ofnondestructive editing (S902). If all of the values are 1, whether thenext file corresponding to the entry is a control movie file or anondestructive editing movie file is identified. More specifically, thereferred-counters of the respective entries being listed are examined(S903). If none of these entries is 2 or more, the type of the file isdetermined as a control movie file, i.e. an original file (S904). Inother words, it is determined that the file is not a movie filegenerated as a result of nondestructive editing. In this manner, thedetermination is carried out in accordance with the referred-counterswhich are information regarding the relationship with the data managedby other entries.

If at least one of the referred-counters is 2 or more in S904, thecreation-time of the file corresponding to the entry in which thereferred-counter is 2 or more is compared with the creation-times ofentries corresponding to other files referring to that filecorresponding to the entry in which the referred-counter is 2 or more.If the creation-time of the file corresponding to the entry in which thereferred-counter is 2 or more is the earliest, the file is identified asa control movie file (original file). Else, the file is identified as anondestructive editing movie file (S905).

When, for instance, the above-described steps are carried out withrespect to the control movie file 1803, the steps S901, S902, S903, andS904 are carried out, and in S905, the creation-time of the controlmovie file 1803 is compared with the creation-time of another movie file1806. As a result, the control movie file 1803 is identified as anoriginal file. As to the movie files 1805 and 1806, these steps revealthat these files are determined as nondestructive editing movie files.

Note that, although in the present case the creation-time in theattribute information entry is used as a criterion for judgment, aduration may be used instead of the creation-time. More specifically,the file is identified as a control movie file if the total durations ofthe AV files being referred to are identical with the duration of thedesignated movie. In other words, the file is identified as not being amovie file generated as a result of the nondestructive editing. If not,the file is identified as a nondestructive editing movie file.

Now, a further description is given with reference again to FIG. 23. Ifthe AV file corresponding to the designated entry is non-original, thefile is determined as erasable (S804). If the AV file is original, theprocess goes to the next step S805. Subsequently, the referred-countersof the AV files to which the AV file of the designated entry refers toare checked (S805). The erasure is allowed if all of thesereferred-counters are 1. Else, the erasure is not allowed (S806).

Now, how the steps after the erasure is allowed and actually carried outare described. If what has been erased was a control movie file, notonly that control movie file but also automatically-divided movie filesto which that control movie file referred are erased.

If, meanwhile, what has been erased was a nondestructive editing moviefile, in addition to the erasure of that file, the referred-counter ofthe entry corresponding to the AV file to which the erased file referredto is reduced by 1, and from the referring-file-list, the entry-numberof the entry corresponding to that erased file is deleted. If what hasbeen erased was other than the above, no further actions have to betaken other than the erasure of the file. Note that, the entry of the AVIndex file corresponding to the erased AV file is of course deleted.

In this manner, in the steps S803 and S804, whether or not an entry iserasable is determined by checking whether or not that entry isoriginal, and the erasure is carried out accordingly. Thus, the erasurecan be carried out without making the user feel uncomfortable, even ofan automatically-divided movie file exists.

In the arrangement above, as described with reference to FIG. 23,whether or not a file is original (i.e. whether or not the file isinitially-recorded data) is determined in S804. The file beingidentified as original is determined as erasable if all of thereferred-counters of the files to which the original file refers to are1, while the original file is determined as non-erasable when at leastone of the referred-counters of the files to which the original filerefers to is not 1.

Thus, when whether or not the control movie file 1803 shown in FIG. 22is erasable is determined, one of the referred-counters of the files1801 and 1802 to which the file 1803 refers is not 1, and are referredto by another movie file 1806, so that the file 1803 is determined asnon-erasable.

Meanwhile, when whether or not the control movie file 1803 in FIG. 21 iserasable is determined, the referred-counters of the files 1801 and 1802which are the targets of the reference are both 1, so that the file 1803is determined as erasable. On the occasion of erasing this file 1803,the files 1801 and 1802 being referred to are also erased.

In this manner, even if an automatically-divided movie file exists, thefile is erased only when the automatically-divided movie file isreferred to only by a control movie file and not by other files. Thus,the erasure is carried out without making the user feel uncomfortable.Furthermore, reference movies (automatically-divided movie and controlmovie) are managed without making the user feel be puzzled.

Furthermore, as described with reference to FIG. 24, in the steps S901through S905, whether or not a registered entry is original isdetermined with reference to the information regarding the divisionalrecording, the information regarding the relationship with data managedby another entry, and the creation-time. This ensures correctdetermination as to whether or not the entry is original.

<Steps for Erasure (Based on Operation Guideline 2)>

In the example shown in FIG. 22, the referred-counters of the entrieswhose entry-numbers are 3, 5, and 6 are 0, so that it can be determinedthat these entries are not referred to by an AV file corresponding toanother entry. Thus, when the user designates these entries whoseentry-numbers are 3, 5, and 6 as targets of erasure, these entries areerased. Meanwhile, when the user designates an entry whose entry-numberis 4 as a target of erasure, the erasure is rejected or a warning isgiven to the user.

The erasure in reality is carried out in the following manner: First,the referred-counter of the entry corresponding to the AV file to whichthe file designated to be erased refers is reduced by 1, and the entrynumber of the entry corresponding to that AV file is deleted from thereferring-file-list. If the referred-counter is reduced to 0, that AVfile is erased. At the end, the AV file designated to be erased iserased. Note that the entry of the AV Index file corresponding to theerased AV file is also erased as a matter of course.

Second Embodiment

The following will discuss Second Embodiment of the present inventionwith reference to FIGS. 25-27. In this embodiment, a flag for tellingwhether or not attribute information of an AV Index file isinitially-recorded data is included in the attribute information of theV Index file, in addition to the flag for telling whether or not theattribute information is an automatically-divided movie file. Based onthis, image reproductions and deletion of files are properly carriedout, thereby preventing the user from being confused. Second Embodimentcan resolve the below-mentioned problem, which is raised when a built-inclock of the recording device is not accurate. As First Embodiment andthe present embodiment have many features in common, the descriptionsare given only to those different from the above.

<Management Information Format>

The formats of a Quicktime movie file and an AV Index file have alreadybeen described above. In the present embodiment, a pe-flags field in aProperty entry of an AV Index file is defined as shown in FIG. 25. Thepe-flags includes, for instance, a Structural status of corresponding AVFile flag. This arrangement is identical with that in First Embodiment,except that a flag for telling whether the AV file corresponding to theentry is original or is generated by editing, termed “Type ofcorresponding AV File”, is added. When the value of this Type ofcorresponding AV File is 0, the AV file is identified as an original(not edited) AV file. When the value of the Type of corresponding AVFile is 1, it is identified that the AV file is an AV file generated byediting. In other words, The Type of corresponding AV File flag isequivalent to information for identifying whether or not the datamanaged by the entry is initially-recorded data.

A description of this flag is given. In First Embodiment, a distinctionis made as to whether the file is an original file or a nondestructiveediting file, on the occasion of carrying out the erasure, as shown inFIG. 23. Note that, the original file in this case is aninitially-recorded file of an image taken by the user. On this occasion,the distinction is made based on the creation-times as shown in FIG. 24.However, this may not be correctly carried out if a built-in clock ofthe recording device is not accurate. Using the above-mentioned flagmakes it possible to make a distinction as to whether the file is anoriginal file or a nondestructive editing file, without relying on sucha built-in clock. The present embodiment is also identical with FirstEmbodiment to the point where the number of times a file managed by thecorresponding entry is referred to by another file is indicated in thereferred-counter of attribute information of the Movie atom of the AVIndex file.

<Steps for Recording>

Descriptions regarding the steps carried out when the user instructsrecording are not given as being basically identical with those of FirstEmbodiment. It is noted that, however, in the present embodiment, asshown in FIG. 26, the Type of corresponding AV File added to theattribute information entry of the AV Index file is set to 0.

<Steps for Nondestructive Editing>

A method of managing the AV Index file on the occasion of carrying outthe nondestructive editing is basically identical with that in FirstEmbodiment, so that the descriptions thereof are omitted. It is notedthat, however, in the present embodiment, as shown in FIG. 27, the Typeof corresponding AV File flags in the attribute information of the AVIndex file, the flags corresponding to nondestructive-edited movie files1805 and 1806, are set to 0.

<Steps for Showing Contents Selection Display>

To the user, thumbnail images corresponding to the attribute informationentries in which the Structural status of corresponding AV Files of thepe-flags are set to 0 are displayed. In the example shown in FIG. 27,thumbnail images corresponding to the entry-numbers 3, 4, 5, and 6 aredisplayed.

<Steps for Erasure>

As in First Embodiment, either Operation Guideline 1 or OperationGuideline 2 can be exercised when the user instructs the erasure throughthe contents selection display. The following will discuss the steps forexercising these operation guidelines.

<Steps for Erasure (Based on Operation Guideline 1)>

The steps carried out when the user instructs the erasure through thecontents selection display are basically identical with those describedin First Embodiment with reference to FIGS. 23 and 24. However, in thepresent embodiment, in the step S803 shown in FIG. 23, whether the AVFile corresponding to the designated entry is generated through thenondestructive editing or is original is determined in such a mannerthat, the AV File is judged as the product of the nondestructive editingwhen the Type of corresponding AV File of the pe-flags of the designatedentry is 1, while the AV File is judged as original when the Type ofcorresponding AV File of the pe-flags of the designated entry is 0. Tothis extent, the steps for the erasure in the present embodiment aredifferent from those in First Embodiment.

As described above, the present embodiment is arranged such that whetheror not the AV Index file is original is determined with reference to theType of corresponding AV File flag in the AV Index file. This flag isgenerated on the occasion of creating a file by recording,nondestructive editing and the like. For this reason, this makes itpossible to surely determine whether or not the file is original.

In First Embodiment, the distinction is made based on the creation-timeso that an error may occur if a built-in clock of the recording deviceis not accurate. On the other hand, the present embodiment has such anadvantage that the process is correctly carried out irrespective of theaccuracy of the built-in clock.

As in First Embodiment, even if an automatically-divided movie fileexists, the file is erased only when the automatically-divided moviefile is referred to only by a control movie file and not by other files.Thus, the erasure is carried out without making the user feeluncomfortable. Furthermore, reference movies (automatically-dividedmovie and control movie) are managed without making the user feel bepuzzled.

<Steps for Erasure (Based on Operation Guideline 2)>

The steps for erasure based on Operation Guideline 2 are identical withthose in First Embodiment. That is to say, in an example shown in FIG.27, the referred-counters of the entries whose entry-numbers are 3, 5,and 6 are set to 0, indicating that these entries are not referred to byan AV file corresponding to another entry. Thus, when the userdesignates these entries whose entry-numbers are 3, 5, and 6 as targetsof erasure, these entries are erased. Meanwhile, when the userdesignates an entry whose entry-number is 4 as a target of erasure, theerasure is rejected or a warning is given to the user.

The erasure in reality is carried out in the following manner: First,the referred-counter of the entry corresponding to the AV file to whichthe file designated to be erased refers is reduced by 1, and the entrynumber of the entry corresponding to that AV file is deleted from thereferring-file-list. If the referred-counter is reduced to 0, that AVfile is erased. At the end, the AV file designated to be erased iserased. Note that the entry of the AV Index file corresponding to theerased AV file is also erased as a matter of course.

Third Embodiment

The following will describe Third Embodiment of the present inventionwith reference to FIGS. 28-32. In the present embodiment, a flag fordetermining whether or not data is presented to the user is included inthe attribute information of the AV Index file, in addition to the flagfor telling whether or not attribute information is initially-recordeddata and the flag for telling whether or not the attribute informationis an automatically-divided movie file. Based on this, imagereproductions and deletion of files are properly carried out, therebypreventing the user from being confused. As First and Second Embodimentsand the present embodiment have many features in common, thedescriptions are given only to those different from the above.

<Management Information Format>

The formats of a Quicktime movie file and an AV Index file have alreadybeen described above. In the present embodiment, a pe-flags field in aProperty entry of an AV Index file is defined as shown in FIG. 28. Thepe-flags includes, for instance, a Structural status of corresponding AVFile flag and a Type of corresponding AV File flag. This arrangement issubstantially identical with that in Second Embodiment, except that aflag called a Visual Status of Type of corresponding AV File indicatingwhether or not the entry is presented to the user by, for instance, thecontents selection display is added (the flag is 0 when the entry ispresented to the user, while the flag is 1 when the entry is notpresented to the user). This Visual Status of Type of corresponding AVFile flag is equivalent to information for deciding whether or not datamanaged by an entry is presented to the user.

The addition of this field makes it possible to select an alternativeoperation guideline for the erasure as discussed below, in addition tothe operation guidelines for the erasure described in First and SecondEmbodiment.

Note that, the present embodiment is also identical with the embodimentsabove to the point where the number of times a file managed by thecorresponding entry is referred to by another file is indicated in thereferred-counter of attribute information of the Movie atom of the AVIndex file.

<Steps for Recording>

Descriptions regarding the steps carried out when the user instructsrecording are not given as being basically identical with those of theforegoing embodiments. It is noted that, however, in the presentembodiment, as shown in FIG. 29, Visual status of corresponding AV Fileflags added to the attribute information entries of the AV Index fileare set to 1 for automatically-divided movie files 1801 and 1802, andare set to 0 for a control movie file 1803 and a normal movie file 1804.

<Steps for Nondestructive Editing>

A method of managing the AV Index file on the occasion of carrying outthe nondestructive editing is basically identical with that in SecondEmbodiment, so that the descriptions thereof are omitted. It is notedthat, however, in the present embodiment, as shown in FIG. 30, VisualStatus of corresponding AV File flags in the attribute informationentries of the AV Index file, the entries corresponding tonondestructive-edited movies 1805 and 1806, are set to 0.

<Steps for After-Recording>

Audio after-recording is carried out with respect to the Av file 1804 inFIG. 29. Supplied audio data is, as shown in FIG. 31, stored in an AVfile 1807 which is different from a file to which the previous movie isstored, and this AV file 1807 is caused to be externally referred to bythe AV file 1804. On this occasion, the referred-counter of an entry(entry-number 5) corresponding to the AV file 1807 is set to 1 as beingreferred to by the AV file 1804, and the referring-file-list records 4which is the entry-number corresponding to the AV file 1804.

Since the AV file 1807 is in subordination to the AV file 1804 and thusnot to be treated as an independent content, the AV file 1807 is notshown on the contents selection display. Thus, a value of the Visualstatus of corresponding AV File is set to 1 (invisible).

<Steps for Showing Contents Selection Display>

To the user, thumbnail images corresponding to the attribute informationentries in which the Structural status of corresponding AV Files of thepe-flags are set to 0 are displayed. In other words, which thumbnailimage is displayed is determined in accordance with the Visual status ofcorresponding AV File flags. For instance, in the example shown in FIG.30, thumbnail images having the entry-numbers 3, 4, 5, and 6 aredisplayed. In the example shown in FIG. 31, meanwhile, thumbnail imageshaving the entry-numbers 3 and 4 are displayed and a thumbnail imagecorresponding to the AV file 1807 which is not to be treated as anindependent content is not displayed. In this manner, unnecessaryinformation is not displayed, and hence the user is unlikely to bepuzzled. This advantage is achieved by the addition of the Visual statusof corresponding AV File in the present embodiment.

<Steps for Erasure>

In the present embodiment, the following operation guideline can beimplemented in addition to those in First and Second Embodiments, whenthe user instructs the erasure through the contents selection display.

(Operation Guideline 3) All AV files are erasable.

This operation guideline 3 is based on such an idea that the differencebetween the original and the edited is caused to be unnoticeable for theuser as much as possible. Note that this operation guideline 3 isrealized by management information which is introduced in ThirdEmbodiment.

The following will discuss the steps for implementing the respectiveoperation guidelines.

<Steps for Erasure (Based on Operation Guideline 1)>

The steps carried out in this case are identical with those in SecondEmbodiment. That is, the steps carried out when the user instructs theerasure through the contents selection display are basically identicalwith those described in First Embodiment with reference to FIGS. 23 and24. However, in the present embodiment, in the step S803 shown in FIG.23, whether the AV File corresponding to the designated entry isgenerated through the nondestructive editing or is original isidentified in such a manner that, the AV File is judged as the productof the nondestructive editing when the Type of corresponding AV File ofthe pe-flags of the designated entry is 1, while the AV File is judgedas original when the Type of corresponding AV File of the pe-flags ofthe designated entry is 0. To this extent, the steps for the erasure inthe present embodiment are different from those in First Embodiment.

In this manner, the present embodiment is arranged such that whether ornot the AV Index file is original is determined with reference to theType of corresponding AV File flag in the AV Index file. This flag isgenerated on the occasion of creating a file by recording,nondestructive editing and the like. For this reason, this makes itpossible to surely identify whether or not the file is original.Furthermore, the present embodiment has such an advantage that theprocess is correctly carried out irrespective of the accuracy of thebuilt-in clock.

As in the foregoing embodiments, even if an automatically-divided moviefile exists, the file is erased only when the automatically-dividedmovie file is referred to only by a control movie file and not by otherfiles. Thus, the erasure is carried out without making the user feeluncomfortable. Furthermore, reference movies (automatically-dividedmovie and control movie) are managed without making the user feel bepuzzled.

<Steps for Erasure (Based on Operation Guideline 2)>

The steps carried out in this case are identical with those in FirstEmbodiment. That is, in an example shown in FIG. 30, thereferred-counters of the entries whose entry-numbers are 3, 5, and 6 areset to 0, indicating that these entries are not referred to by an AVfile corresponding to another entry. Thus, when the user designatesthese entries whose entry-numbers are 3, 5, and 6 as targets of erasure,these entries are erased. Meanwhile, when the user designates an entrywhose entry-number is 4 as a target of erasure, the erasure is rejectedor a warning is given to the user.

The erasure in reality is carried out in the following manner: First,the referred-counter of the entry corresponding to the AV file to whichthe file designated to be erased refers is reduced by 1, and the entrynumber of the entry corresponding to that AV file is deleted from thereferring-file-list. If the referred-counter is reduced to 0, that AVfile is erased. At the end, the AV file designated to be erased iserased. Note that the entry of the AV Index file corresponding to theerased AV file is also erased as a matter of course.

<Steps for Erasure (Based on Operation Guideline 3)>

The following will discuss the operation such that all entries which areinstructed by the user to erase through the contents selection displayare erasable. The steps for the erasure in this case are described withreference to FIG. 32. First, to check whether or not an AV filecorresponding to the designated entry is referred to by another AV file,the referred-counter of the designated entry is examined (S1001).

If the referred-counter is 1, a Visual status of corresponding AV Fileis set to 1 (S1006). This allows the user to recognize that the file iserased, without causing any influence on the playing of other movies. Inother words, the file is apparently erased. In this case, the Visualstatus of corresponding AV File flag is altered to 1 from 0. If thereferred-counter is 0, whether or not the AV file corresponding to thedesignated entry refers to another AV file is checked (S1002).

If not referring to another file, the below-mentioned step S1005 iscarried out. If referring to another file, first, the referred-counterof the entry corresponding to the AV file which is the target of thereference is reduced by 1 (S1003).

Next, values of the referred-counter and Visual status of correspondingAV of the target AV file are checked. If the referred-counter is 0 andthe Visual status of corresponding AV is 1 (invisible), the file iserased, and the entry concerning the file is deleted from the AV Indexfile (S1004). Lastly, the AV file corresponding to the designated entryis erased (S1005).

Referring to FIG. 30, the above-mentioned steps are described morespecifically. When entries having entry-numbers 5 and 6 are designatedas targets of erasure, these entries are erased and a file 1805 or 1806is further erased. When an entry having an entry-number 3 is designatedas a target of erasure, that entry is erased and a file 1803 is alsoerased. However, files 1801 and 1802 which are the targets of referenceare also referred to by a file 1806, thereby not being erased.

When an entry having an entry-number 4 is designated as a target oferasure, a file 1804 corresponding to that entry is not deleted as beingreferred to by a file 1805. Instead of erasing the file, the Visualstatus of corresponding AV File is set to 1.

The same holds true for the example in FIG. 31. When an entry having anentry-number 4 is designated as a target of erasure, thereferred-counter of this entry is 0 and the referred-counter of an AVfile 1807 referred to by the entry is reduced by 1 so as to be 0. Thus,entries having entry-numbers 4 and 5 are erased, and AV files 1804 and1807 corresponding to these entries are also erased.

In this manner, the present embodiment adopts a Visual status ofcorresponding AV File indicating whether or not data is presented to theuser by the contents selection display. On this account, the user canerase any arbitrary content even if the content refers to a file. Inother words, even a file which is referred to by another file can beapparently erased, i.e. caused not to be displayed.

<Variants>

In First through Third Embodiments of the present invention, AV Indexfiles manage files stored in the same storage medium. However, as amatter of course, AV Index files may manage a file in a differentstorage medium, e.g. a file in a remote storage medium via a network.

In the embodiments above, the descriptions were given on assumption thata storage medium is the optical disk 106. However, since the presentinvention is not limited to this arrangement, the storage medium may beother types of random-access storage media such as a hard disk and amagneto-optical disk.

In the embodiments above, the descriptions were given on assumption thatthe UDF is adopted as a file system and the Quicktime file format isadopted as a file format. However, since the present invention is notlimited to this arrangement, other types of file systems and fileformats may be adopted.

In the embodiments above, the descriptions were given on assumption thatthe file management is carried out using an AV Index file based on theQuicktime file format. However, since the present invention is notlimited to this arrangement, the file management may be carried outusing other types of files and tables.

As described above, in the foregoing embodiments, the digitalrecording/reproducing device is, as a storage device, arranged in such amanner that the host CPU 101 as a file management section records, tothe optical disk 106, information regarding whether or not data isdivisional-recorded.

For this reason, files are appropriately displayed, erased and so on inaccordance with the information regarding whether or not data isdivisional-recorded, so that the file management is carried out withoutmaking the user feel be puzzled.

That is to say, with regard to divided data when the divisionalrecording is carried out and control data referring to the divided data,the divided data is caused not to be displayed.

This divided data is generated by, because there is an upper limit ofthe file size in the file system, dividing a file exceeding the upperlimit. As described above, causing the divided data not to be displayedeliminates the probability of making the user be perplexed.

To erase control data, divided data referred to by the control data isalso erased if the divided data is referred to by only the control data.

With this, even if divided data exists, the erasure is carried outwithout causing the user to notice the existence of such data. Note thatthe erasure of data is allowed when the data is not referred to byanother file.

Furthermore, the digital recording/reproducing device is, as a storagedevice, arranged in such a manner that the host CPU 101 as a filemanagement section records, to the optical disk 106, informationregarding whether or not data is initially-recorded data.

For this reason, files are appropriately displayed, erased and so on inaccordance with the information regarding whether or not data isinitially-recorded data, so that the file management operations such asdisplay and erasure is properly carried out without making the user feelbe puzzled.

That is, when there are divided data as a result of divisional recordingand control data referring to the divided data, it is possible to tellwhether or not a set of data is control data, by the informationregarding whether or not data is initially-recorded data. Since it isunnecessary to check information such as the creation time of the file,the type of the data is surely detected even if a built-in clock of thestorage device is not accurate.

Furthermore, the digital recording/reproducing device is, as a storagedevice, arranged in such a manner that the host CPU 101 as a filemanagement section records, to the optical disk 106, informationregarding whether or not the presence of data is displayed to the user.

With this, files are displayed, apparently erased and so on in anappropriate manner in accordance with the information regarding whetheror not the presence of data is displayed to the user, so that the filemanagement operations such as display and erasure is properly carriedout without making the user feel be puzzled.

That is, images are displayed in accordance with the informationregarding whether or not the presence of data is displayed to the user,in addition to the information indicating whether or not data is divideddata. This makes it possible to display images without making the userfeel be puzzled, and apparently erase data.

Furthermore, to the optical disk 106 the information regarding whetheror not data is initially-recorded data is recorded as described above.

Thus, the optical disk 106 is combined with a storage device such as theaforementioned digital recording/reproduction device, and files areappropriately displayed, erased and so on in accordance with theinformation regarding whether or not data is initially-recorded data, sothat the file management operations such as display and erasure areproperly carried out without making the user feel be puzzled.

Furthermore, to the optical disk 106 the information regarding whetheror not the presence of data is displayed to the user is recorded asdescribed above.

Thus, the optical disk 106 is combined with a storage device such as theaforementioned digital recording/reproduction device, and files aredisplayed, apparently erased and so on in an appropriate manner inaccordance with the information regarding whether or not the presence ofdata is displayed to the user, so that the file management operationssuch as display and erasure are properly carried out without making theuser feel be puzzled.

The digital recording/reproduction device as a storage device may berealized using a computer. That is to say, the aforementioned digitalrecording/reproduction device may be realized in such a manner that aprogram for implementing either the above-mentioned data recordingmethod or the above-mentioned data erasure method is read and ran by acomputer.

The above-mentioned data recording method and data erasure method can beillustrated as, for instance, a file management method for managing datausing file management information of a file system. When the fileincludes a divided file and a control file referring to the dividedfile, the file management information in accordance with the filemanagement method is caused to include a flag indicating whether or notthe file is a divided file. Based on (i) this flag, (ii) the number oftimes a file is referred to by other files, and (iii) the creation timeof the file, it is possible to tell whether or not the file is a controlfile.

Also, the above-mentioned arrangement can be, for instance, illustratedas a data erasure method for erasing, from a storage medium including atable centrally managing sets of data, the sets of data corresponding tothe entries in the table, the data erasure method being characterized bycomprising the step of determining whether or not the registered entryis original, on the occasion of the erasure.

Also, the above-mentioned arrangement can be, for instance, illustratedas a data erasure method characterized in that the foregoing step ofdetermining whether or not the registered entry is original is carriedout based on the information regarding whether or not automatic divisionis carried out, the information concerning reference to another sets ofdata, and a creation time.

Also, the above-mentioned arrangement can be, for instance, illustratedas a data recording method for recording a table, which centrallymanages sets of data as respective entries, to a storage medium, thedata recording method being characterized in that, to the entriescorresponding to the sets of data, information for making it possible todetermine whether or not data is original is recorded.

Also, the above-mentioned arrangement can be, for instance, illustratedas a data erasure method for erasing, from a storage medium whichincludes a table for centrally managing sets of data as respectiveentries and stores information for determining whether or not theseentries are original, the sets of data corresponding to the entries inthe table, the data erasure method being characterized in that, on theoccasion of the erasure, whether or not the data which is the target ofthe erasure can be erased in accordance with the information regardingwhether or not data is original.

Also, the above-mentioned arrangement can be, for instance, illustratedas a data recording method for recording, to a storage medium, a tablewhich centrally manages sets of data as respective entries, the datarecording method being characterized in that the entries correspondingto the sets of data record information regarding whether or not theexistence of the sets of data is displayed to the user.

Also, the above-mentioned arrangement can be, for instance, illustratedas a data erasure method for erasing, from the storage medium whichincludes a table centrally managing sets of data as respective entriesand records, to the entries, information regarding whether or not theexistence of these sets of data is displayed to the user, the sets ofdata corresponding to the entries in the table, the data erasure methodbeing characterized in that, if a set of data to be erased is referredto by another set of data, the information regarding whether or not theexistence of data is displayed to the user is rewritten.

The present invention realizes the following: Based on the informationfor determining whether or not files on the disk areautomatically-divided movie files and the information for determiningwhether or not the files are original, the erasure is carried outwithout making the user feel be puzzled, despite the presence of anautomatically-divided movie file.

The present invention realizes the following: The information regardingwhether or not data is original is stored in the disk, so that theerasure is carried out without making the user feel be puzzled, despitethe presence of an automatically-divided movie file.

The present invention realizes the following: With respect to the AVfile corresponding to the entry, the information for determining whetheror not data is displayed to the user is stored in the disk, so that theuser can apparently erase any set of data even if the data refers to afile.

Note that, as shown in FIG. 36, the following arrangement may be carriedout: To each entry of an index file 2100, an auto-divided flagindicating whether or not the entry is an automatically-divided movie isprovided. Files 2201 through 2203 which are automatically-divided moviesare set to YES, so that, on the contents selection display, only aminiature image of an entry in which the auto division is NO, i.e. onlya miniature image of a file 2204 is shown. However, in this arrangement,it is unclear how management operations, e.g. erasure, are carried out.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art intended tobe included within the scope of the following claims.

Matters described in claims and technical means described in Embodimentscan be appropriately combined with each other, and matters obtained as aresult of the combination are not to be regarded as a departure from thespirit and scope of the invention.

INDUSTRIAL APPLICABILITY

According to a data recording method, data erasure method, data displaymethod, storage divide, storage medium, and program, an index filemanages sets of information for determining (i) whether or not managedfiles are displayed to the user, (ii) whether or not the managed filesare original, and (iii) whether or not the managed files have beensubjected to nondestructive editing, and in accordance with these setsof information, the steps for erasure and the steps for showing a filelist are carried out. This makes it possible to manage reference moviesby the index file, without making the user feel be puzzled.

1. A data erasure method for erasing a set of data corresponding to anentry in a table from a storage medium, the table being stored in thestorage medium and centrally managing sets of data at least includingsets of divided data and control data referring to said sets of divideddata, the data erasure method comprising the step of: (i) said set ofdata is erased, identifying whether or not said set of datacorresponding to said registered entry is initially-recorded data. 2-16.(canceled)